By Meetu Jain
NEW DELHI, September 17, 2025: Delhi’s marvelous Red Fort (Lal Quila), built by the 17th century Mughal emperor Shah Jahan, is finally stumbling to pollution, with Delhi being one of the most polluted city in the world. A study by MDPI-Heritage reveals black-crusts have emerged on the walls of the fort. “The Red Fort, a UNESCO World Heritage Site and a symbol of India’s rich history, is highly susceptible to degradation caused by air pollutants,” says the report.
The Red Fort has historical significance, where India’s first Prime Minister Jawaharlal Nehru raised India’s tricolour flag on 15 August, 1947, after independence from the Britain, after around 200 years (combined East India Company and the British Raj). The INA (Indian National Army) trials (court-martials) of 1945 and 1946, were held in the Red Fort with charges of treason, torture, murder and abetment to murder against prominent leaders and other members of the INA led by Netaji Subhash Chandra Bose, by the British rulers.
Various sources in the Indian media citing the report, say that the black crusts are deposits created by chemical reactions between airborne pollutants and the fort’s red sandstone walls, reaching thicknesses between 0.05mm and 0.5mm. The formation of these crusts, which contain heavy metals like lead, copper, zinc, gypsum, and other compounds, is damaging the fort’s intricate stone carvings, causing flaking, blistering, and loss of detail in architectural features. The pollution is mainly from vehicular emissions, construction dust, and industrial pollutants, with particulate matter (PM2.5 and PM10) and nitrogen dioxide levels consistently exceeding safe limits in the area.
The study says, ” The primary objective of this study was to analyze the chemical composition of the back crusts affecting the conservation of the Red Fort complex and to investigate their possible origin. A preliminary overview of the air quality surrounding the Red Fort complex is presented based on the data from the Central Pollution Control Board (CPCB). Subsequently, selected degraded and non-degraded stone samples are examined, applying a range of multi-analytical techniques, including Field Emission Scanning Electron Microscopy-Energy Dispersive X-ray spectroscopy (FE-SEM-EDX), X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Finally, the composition of these samples and the air quality data are discussed to explore possible links and impacts on the conservation of the Red Fort complex,” the report says.
The research is based on the analysis of data from 2021, 2022,and 2023, by Indian and Italian researchers from institutions including IIT Roorkee, Archaeological Survey of India, Ca’ Foscari University of Venice, Italy, IIT Kanpur among others, is the first comprehensive scientific probe of this type.
An urgent move towards the Red Fort’s structural and aesthetic integrity, and conservation has been recommended by experts to stop further degradation of the historical monument.
